Composting: Biology Curriculum

Transcription

1 Cornell Waste Management Institute cwmi.css.cornell.edu Composting: Biology Curriculum Understanding what composting is and how it works. Table of Contents Goal, Objectives, Keywords, Scientific Concepts... 1 Discover Composting Organisms... 2 Food Web Game... 3 Watching Wastes Rot... 5 Watching Wastes Rot Record... 6 Other Resources for Composting: Biology... 7 Handouts: What Lives In Compost: Spanish English Food Web Game pieces: Spanish English

2 Puerto Rico Curriculum Composting: Biology 1 Section 2: Composting: Biology Goal: To understand what composting is and how it works Objectives: At the end of this unit, students should be able to 1. Describe the process of composting. 2. Identify compost workers 3. Understand the cycle for organic materials. 4. Determine what types of materials decompose. Keywords: organics, compost, composting, microorganisms, macro organisms, decomposition, nutrient cycle, primary and secondary decomposers/consumers, predators Scientific Concepts: Observing, communicating, comparing, ordering, relating Activities: 1. Discover Composting Organisms from Composting: Wastes to Resources, Cornell University 2. Food Web Game: Courtesy of Allison L H Jack, Department of Plant Pathology and Plant Microbe Biology, Cornell University, Ithaca, NY 3. Watching Wastes Rot from Composting: Waste to Resources

3 Puerto Rico Curriculum Composting: Biology 2 Activity 1: Discover Composting Organisms Grade Level: All grades and ages Background: Composting, a biological process, occurs naturally nearly everywhere! Leaves drop from plants and trees. Plants and animals die. Over time, these organic materials break down or decompose. The rich, dark, soil like material that results is called compost. Tiny living organisms do much of the work of breaking down organic materials to form compost. These tiny workers are called microorganisms and include such things as bacteria and fungi. Larger organisms, such as worms and pill bugs are examples of soil creatures that help change organic wastes into compost. When we build a compost pile, we need to create a habitat or home where the living organisms have food shelter and moisture. As microorganisms and soil creatures turn organic materials into compost, they use the organic materials as food. The organic materials provide nutrients for growth and activity. Eventually, these nutrients are returned to the soil, to be used again by plants. This is nature s way of recycling! Materials: Vermicomposting video available at What Lives in Compost handout Sample of Compost Glass slide Hand lens or microscope Procedure: In this activity we will explore the micro and macro organisms that do the work of decomposition in a compost pile. The insects, worms, bacteria, and fungi found in a compost pile do the work of making compost. You can see some soil animals with the naked eye, and for some you will need a hand lens or microscope. 1. Show Vermicompost a Living Soil Amendment from 0:48 to 2:30 (The biology of Vermicomposting) 2. Put a small compost sample on a glass slide with a drop of water. Observe the sample under a hand lens or microscope. Draw pictures of what you see or check them off on the handout. Try to identify the organisms using the handout or information found online (see additional resources below). Follow up: 1. Take a field trip to see a compost pile, and bring a hand lens to do on site investigations 2. Discuss what would happen in the world if there were no decomposers. What would happen to leaves in the fall, or to dead trees in the forest? (Decomposers are the recyclers of the natural world. They break down organic matter and turn it into materials that can once again be used to support life. That is why compost contains many nutrients that help plants to grow. Without decomposers, we would all be buried in wastes!)

4 Puerto Rico Curriculum Composting: Biology 3 Activity 2: Food Web Game Grade Level: Grade 5 and older Background: We have seen that insects, worms, bacteria and fungi do the work of making compost (converting organic matter, such as banana peels and leaves into a soil like material). Each of these has a job in the food chain of the compost pile. Primary decomposers or consumers eat organic matter. Secondary consumers eat the primary consumers and predators, and third level consumers eat secondary consumers. We will replicate a compost web in the classroom. Materials: Food web game pieces one for each student (see handouts on cover page) Yarn or string cut into long pieces enough for each student to get multiple pieces Food Web of the Compost Pile (see below) Procedure: Distribute one card and a few pieces of string to each student. Start with Organic matter holding one end of a string and ask who eats organic matter? then hand the other end of the string to the person acting as bacteria for example. Continue building the food web in this fashion until everyone is connected as shown below: Point out that arthropods form the base of land based food webs and are eaten by small animals and birds, etc. If the students are old enough, using the Food Web of the Compost Pile picture, have them identify themselves as primary or secondary consumers, predators, etc.

5 Puerto Rico Curriculum Composting: Biology 4

6 Puerto Rico Curriculum Composting: Biology 5 Activity 3: Watching Wastes Rot Grade Level: Grades 4 and older Background: Microorganisms and soil animals do most of the work of breaking down wastes in compost. Do you think wastes will break down if these organisms are not present? How long do you think it will take? Some wastes break down faster than others and some will never break down in a compost pile. Which ones will never break down and why? In this lesson, we will explore how composting works and observe how fast certain items decay. Materials: How Does Composting Work? poster in Spanish and English available at: Watching Wastes Rot Record (page 6) 16 oz. containers (remember to re use food containers such as cottage cheese or yogurt containers) Compost sample Sterile potting soil, perlite or vermiculite Organic wastes, such as orange, banana or mango peels, lettuce or other fruit or vegetable wastes Paper wastes, such as paper napkins and paper bags Plastic wastes, such as Styrofoam chips and plastic bags Labels that stick on the containers or permanent marker Procedure: Go over the poster How Does Composting Work and discuss the requirements that the micro and macro organisms need to be able to do their job. 1. Divide the students into groups you can either divide them up as compost and sterile potting soil or as organic and plastic, or let each group do all combinations. 2. Distribute containers, waste material, compost, and sterile potting mix, to each group, depending on how you divided them. 3. Fill half the containers half full with compost. Fill the other half of the pots half full with sterile mix. 4. Divide your organic, paper and plastic wastes up and put half of each in containers with compost and the other half in containers with sterile mix. Make sure you put the same amount of waste into each pot. 5. Label the containers with the names of the wastes. 6. Cover the wastes with compost or sterile mix, filling the pots. Add water to all the containers so that the compost and sterile mix are damp but not wet to the touch. 7. Check your containers every few days to be sure they are still moist. 8. After one week, examine the wastes in each pot. Which wastes are decomposing? 9. Cover the wastes again, and continue to check them once a week for as long as you want. 10. Record your observations in the Watching Wastes Rot Record each time you check. Answer the questions and discuss the answers.

7 Puerto Rico Curriculum Composting: Biology 6 Watching Wastes Rot Record Name: Date experiment started: Fill in the following table each time you check your pots. Under Waste write the name of the item that you buried in the pot. Under Compost describe the condition of the item buried in compost each time you check it. Include such things as how decomposed the item looks, what color it is, and whether or not you see fungi (spots or thin strands) on it. Under Sterile Mix describe, in the same way, the condition of the item buried in sterile mix. Date: Time since waste was buried: Waste Compost Sterile Mix Which items decomposed most quickly? Which items didn t decompose at all? In general, did items decompose more quickly in compost or in sterile mix? Why do you think this is true?

8 Puerto Rico Curriculum Composting: Biology 7 Other Resources for Composting: Biology 1. Natural Forces of Decay and Renewal information on biodegradation (attached) 2. Harnessing Natural Decay information on compost biology and chemistry (attached) 3. Discover Compost Animals from Composting: Waste to Resources (attached) 4. Common Compost Bugs from Compostjunkie.com has some nice pictures of compost organisms bugs.html. 5. Watching Wastes Rot II from Composting: Waste to Resources (page 29). Available at: 6. CalRecycle Closing the Loop: 4 6 Module: Unit 3: Composting. Available at: 7. Reduce Reuse Recycle Rebuy: Tompkins County Lesson Plans for Youth: Composting available at